Bernhard Schussek has written up a new post to the Web Mozarts blog talking about resource discovery with Puli. Puli is a management tool for the non-PHP files in your applications (CSS, Javascript, YAML, etc). In this post he talks about the use of the discovery component and its use of resource binding.

Many libraries support configuration code, translations, HTML themes or other content in files of a specific format. The Doctrine ORM, for example, is able to load entity mappings from special XML files. When setting up Doctrine, we need to pass the location of the *.dcm.xml file to Doctrine's XmlDriver. That's easy as long as we do it ourselves, but what if someone else uses our package? How will they find our file? What if multiple packages provide *.dcm.xml files? How do we find all these files? We need to remove the appropriate setup code after removing a package [and] we need to adapt the setup code after installing a new package. Multiply this effort for every other library that uses user-provided files and you end up with a lot of configuration effort. Let's see how Puli helps us to fix this.

He talks about the concept of package roles in the tool, breaking them down in resources and providers. He then shows how Puli makes it possible to discover resources by defining a type via Puli and the code for the discovery process. He then binds the XML configuration definition and executes a "find" to ensure it's configured correctly. Finally, he shows the process to use Puli in this Doctrine example allowing it to locate and use the XML mappings dynamically via a custom driver.

This first entry is an examination of Yadis, a Specification which is relied upon by OpenID. Of course Yadis is a topic of its own, since it is also used by Light-Weight Identity (LID), sxip Identity, and mIDm. You can bet more will join in once Yadis becomes more firmly established.

In this first part, he talks about what Yadis is, how it can help with service discovery, and how it would follow a "breadcrumb trail" to get to the information it needs (like getting the actual Yadi slocation from the initial OpenID request).

After all this fuss and running about, it's easy to miss the point of Yadis - getting that final Yadis XRD document that describes the Services associated with a given ID.

Part two looks more at working with the Yadis Resource Descriptor information to grap the Type information out of it for the actual locations you'll needed. He also links to some more information on the Yadis specification in PDF form.